BACKGROUND OF THE INVENTION
[0001] Some example embodiments relate to semiconductor devices and/or electronic apparatuses
including the same, and more particularly, to semiconductor devices in which a dielectric
constant of an interfacial insulating layer and a remnant polarization of a ferroelectric
layer are combined to reduce the intensity of an electric field applied to the interfacial
insulating layer, and/or to electronic apparatuses including the semiconductor devices.
[0002] Ferroelectrics are materials having ferroelectricity, for example, they maintain
a spontaneous polarization by aligning internal electric dipole moments even when
no electric field is applied thereto from the outside. Ferroelectrics are materials
in which the polarization (and/or electric field) remains semi-permanent in the material
even when a voltage is brought back to 0V after applying thereto a certain voltage.
Research on applying ferroelectric properties to logic devices and/or memory devices
have been conducted.
SUMMARY
[0003] Provided are semiconductor devices in which the dielectric constant of an interfacial
insulating layer and a remnant polarization of a ferroelectric layer are combined
to reduce the intensity of an electric field applied to the interfacial insulating
layer, and/or an electronic apparatuses including the same.
[0004] Alternatively or additionally, provided are semiconductor devices with reduced operating
voltage and/or electronic apparatuses including the semiconductor devices.
[0005] Alternatively or additionally, provided are semiconductor devices with improved durability
and data retention, and/or electronic apparatuses including the same.
[0006] Additional aspects will be set forth in part in the description which follows and,
in part, will be apparent from the description, or may be learned by practice of various
example embodiments of the disclosure.
[0007] According to an some example embodiment, a semiconductor device includes: a first
source/drain region; a second source/drain region; a channel between the first source/drain
region and the second source/drain region; an interfacial insulating layer on the
channel; a ferroelectric layer on the interfacial insulating layer; and a gate electrode
on the ferroelectric layer. A material of the interfacial insulating layer and a material
of the ferroelectric layer may be selected so that K/Pr is 1 or more, where K is a
(unitless) numerical value of a dielectric constant of the interfacial insulating
layer, and Pr is a numerical value of the remnant polarization of the ferroelectric
layer, where Pr is in the units of microcoulombs per square centimeter (uC/cm
2).
[0008] The dielectric constant of the interfacial insulating layer and the remnant polarization
of the ferroelectric layer may be selected so that a voltage applied to the interfacial
insulating layer during application of an operating voltage to the gate electrode
is less than a breakdown voltage of the interfacial insulating layer.
[0009] For example, the dielectric constant of the interfacial insulating layer may be 22
or more, and the remnant polarization of the ferroelectric layer may be greater than
or equal to 0.1 uC/cm
2 and less than or equal to 15 uC/cm
2.
[0010] For example, the dielectric constant of the interfacial insulating layer may be 14
or more, and the remnant polarization of the ferroelectric layer may be greater than
or equal to 0.1 uC/cm
2 and less than or equal to 10 uC/cm
2.
[0011] For example, the dielectric constant of the interfacial insulating layer may be 7
or more, and the remnant polarization of the ferroelectric layer may be greater than
or equal to 0.1 uC/cm
2 and less than or equal to 5 uC/cm
2.
[0012] For example, a coercive field of the ferroelectric layer may be in a range from about
30 kV/cm to about 3 MV/cm or less.
[0013] For example, the interfacial insulating layer may include at least one material selected
from the group including or consisting of M-Si
xGe
1-x-O (0≤x≤1) and M-Si
xGe
1-x-O
yN
1-y (0≤x≤1, 0≤y≤1), where M includes a metal material.
[0014] For example, the metal material may include at least one material selected from the
group including Ti, Al, Hf, Zr, La, Y, Mg, and Be or a combination thereof.
[0015] For example, the ferroelectric layer may include an oxide of Si, Al, Hf, or Zr such
as one or more of silicon oxide, aluminum oxide, hafnium oxide, or zirconium oxide,
or may include a two-dimensional ferroelectric material.
[0016] The ferroelectric layer may further include a dopant doped in the oxide or the two-dimensional
ferroelectric material, wherein the dopant includes at least one material selected
from the group including Si, Al, Y, La, Gd, Mg, Ca, Sr Ba, Ti, Zr, Hf and N.
[0017] The ferroelectric layer may include at least two dopants different from each other.
[0018] A ratio of the dopant in the ferroelectric layer may be in a range from about 0 at%
to about 90 at%.
[0019] For example, the two-dimensional ferroelectric material may include at least one
material selected from the group including 1T-MoS
2, SnTe, GeSe, 1T-MoTe
2, In
2Se
3, and CuInP
2S
6.
[0020] The semiconductor device may further include a conductor layer between the interfacial
insulating layer and the ferroelectric layer.
[0021] A sum of an area of the interfacial insulating layer in contact with the conductor
layer and an area of the conductor layer in contact with the interfacial insulating
layer may be greater than a sum of an area of the ferroelectric layer in contact with
the gate electrode and an area of the gate electrode in contact with the ferroelectric
layer.
[0022] The semiconductor device may further include a substrate, wherein the channel may
be disposed to protrude from an upper surface of the substrate and may have a shape
extending in a first direction.
[0023] The interfacial insulating layer may be disposed to surround side surfaces and an
upper surface of the channel, the ferroelectric layer may be disposed to surround
side surfaces and an upper surface of the interfacial insulating layer, and the gate
electrode may be disposed to surround side surfaces and an upper surface of the ferroelectric
layer.
[0024] The channel may be disposed to be separated from the upper surface of the substrate
and may extend in a first direction.
[0025] The channel may include a plurality of channel elements disposed at a distance from
each other in a second direction that is different from the first direction.
[0026] The interfacial insulating layer may include a plurality of interfacial insulating
layers disposed to respectively surround the plurality of channel elements, the ferroelectric
layer may include a plurality of ferroelectric layers disposed to respectively surround
the plurality of interfacial insulating layers, and the gate electrode may be disposed
to protrude from the upper surface of the substrate to surround the plurality of ferroelectric
layers.
[0027] According to some example embodiments, a semiconductor device includes: a first source/drain
region; a second source/drain region; a channel between the first source/drain region
and the second source/drain region; an interfacial insulating layer on the channel;
a ferroelectric layer on the interfacial insulating layer; and a gate electrode on
the ferroelectric layer, wherein the interfacial insulating layer may include at least
one material selected from the group including M-Si
xGe
1-x-O (0≤x≤1) and M-Si
xGe
1-x-O
yN
1-y (0≤x≤1, 0≤y≤1), where M includes a metal material, and a coercive field of the ferroelectric
layer may be in a range from about 30 kV/cm to about 3 MV/cm or less.
[0028] According to some example embodiments, an electronic apparatus includes at least
one semiconductor device, wherein each semiconductor device includes: a first source/drain
region; a second source/drain region; a channel between the first source/drain region
and the second source/drain region; an interfacial insulating layer on the channel;
a ferroelectric layer on the interfacial insulating layer; and a gate electrode on
the ferroelectric layer, wherein a material of the interfacial insulating layer and
a material of the ferroelectric layer are such that K/Pr is 1 or more, where K is
a numerical value of dielectric constant of the interfacial insulating layer and Pr
is a numerical value of remnant polarization of the ferroelectric layer in units of
uC/cm
2.
[0029] According to some example embodiments, a semiconductor device includes substrate
including a channel region; an interfacial insulating layer on the channel region;
and a ferroelectric layer directly on the interfacial insulating layer. A first material
of the interfacial insulating layer and a second material of the ferroelectric layer
are such that K/Pr is 1 or more, where K is a numerical value of dielectric constant
of the interfacial insulating layer and PR is a numerical value in uC/cm
2 of a remnant polarization of the ferroelectric layer.
[0030] The semiconductor device may additionally include a gate electrode directly on the
ferroelectric layer.
[0031] The dielectric constant of the interfacial insulating layer and the remnant polarization
of the ferroelectric layer are such that a voltage applied to the interfacial insulating
layer during application of an operating voltage to the gate electrode is less than
a breakdown voltage of the interfacial insulating layer.
[0032] A thickness of the interfacial insulating layer is less than about 2 nm.
[0033] A thickness of the ferroelectric layer is less than about 20 nm.
BRIEF DESCRIPTION OF THE DRAWINGS
[0034] The above and other aspects, features, and/or advantages of certain embodiments of
the disclosure will be more apparent from the following description taken in conjunction
with the accompanying drawings, in which:
FIG. 1 is a schematic cross-sectional view illustrating a structure of a semiconductor
device according to some example embodiments;
FIG. 2 is a graph showing a relationship between a combination of a dielectric constant
of an interfacial insulating layer and a remnant polarization of a ferroelectric layer
and an intensity of an electric field applied to the interfacial insulating layer;
FIG. 3 is a graph showing a comparison of a capacitance-voltage characteristic of
two semiconductor devices including interfacial insulating layers having different
dielectric constant;
FIG. 4 is a graph showing a comparison of switching voltages of two semiconductor
devices each including interfacial insulating layers having different dielectric constants
from each other;
FIG. 5 is a graph showing a comparison of remnant polarizations of two ferroelectric
layers having different doping concentrations from each other;
FIG. 6 is a graph showing a comparison of characteristics of two semiconductor devices
each including ferroelectric layers having different doping concentrations from each
other;
FIG. 7 is a schematic cross-sectional view illustrating a structure of a semiconductor
device according to some example embodiments;
FIG. 8 is a schematic cross-sectional view illustrating a structure of a semiconductor
device according to some example embodiments.
FIG. 9 is a schematic perspective view illustrating a structure of a semiconductor
device according to some example embodiments;
FIG. 10 is a schematic cross-sectional view illustrating a gate structure of the semiconductor
device shown in FIG. 9;
FIG. 11 is a schematic perspective view illustrating a structure of a semiconductor
device according to some example embodiments;
FIG. 12 is a schematic cross-sectional view illustrating a gate structure of the semiconductor
device shown in FIG. 11;
FIG. 13 is a schematic perspective view illustrating a structure of a semiconductor
device according to some example embodiments;
FIG. 14 is a schematic cross-sectional view illustrating a gate structure of the semiconductor
device shown in FIG. 13;
FIG. 15 is a schematic circuit diagram of a memory device including a semiconductor
device array;
FIG. 16 is a schematic cross-sectional view illustrating a structure of a semiconductor
device according to some example embodiments.
FIG. 17 is a schematic block diagram of a display driver IC (DDI) and a display device
including the DDI according to some example embodiments;
FIG. 18 is a block diagram illustrating an electronic device according to some example
embodiments;
FIG. 19 is a block diagram of an electronic device according to some example embodiments;
and
FIGS. 20 and 21 are schematic conceptual diagrams illustrating a device architecture
applicable to an electronic device according to some example embodiments.
DETAILED DESCRIPTION
[0035] Reference will now be made in detail to various embodiments, examples of which are
illustrated in the accompanying drawings, wherein like reference numerals refer to
like elements throughout. In this regard, example embodiments may have different forms
and should not be construed as being limited to the descriptions set forth herein.
Accordingly, various embodiments are merely described below, by referring to the figures,
to explain aspects. As used herein, the term "and/or" includes any and all combinations
of one or more of the associated listed items. Expressions such as "at least one of,"
when preceding a list of elements, modify the entire list of elements and do not modify
the individual elements of the list.
[0036] Hereinafter, a semiconductor device and/or an electronic apparatus including the
same will be described in detail with reference to the accompanying drawings. In the
drawings, like reference numerals refer to like elements, and the size of each component
may be exaggerated for clarity and convenience of explanation. Also, example embodiments
of inventive concepts are capable of various modifications and may be embodied in
many different forms.
[0037] When an element or layer is referred to as being "on" or "above" another element
or layer, the element or layer may be directly on another element or layer or intervening
elements or layers. The singular forms are intended to include the plural forms as
well unless the context clearly indicates otherwise. When a part "comprises" or "includes"
an element in the specification, unless otherwise defined, it does not necessarily
exclude other elements but may or may not further include other elements.
[0038] The term "above" and similar directional terms may be applied to both singular and
plural. With respect to operations that constitute a method, the operations may be
performed in any appropriate sequence unless the sequence of operations is clearly
described or unless the context clearly indicates otherwise.
[0039] Also, in the specification, the term "units" or "...modules" denote units or modules
that process at least one function or operation, and may be realized by hardware,
software, or a combination of hardware and software.
[0040] Connections or connection members of lines between components shown in the drawings
illustrate functional connections and/or physical or circuit connections, and the
connections or connection members may be represented by replaceable or additional
various functional connections, physical connections, or circuit connections in an
actual apparatus.
[0041] The use of all examples or example terms is merely for describing the technical scope
of the inventive concept in detail, and thus, the scope of the inventive concept is
not limited by the examples or the example terms as long as it is not defined by the
claims.
[0042] FIG. 1 is a schematic cross-sectional view illustrating a structure of a semiconductor
device 100 according to some example embodiments. Referring to FIG. 1, the semiconductor
device 100 according to some example embodiments includes a first source/drain region
102 (e.g. a source region), a second source/drain region 103 (e.g. a drain region),
a channel 104 disposed between the first source/drain region 102 and the second source/drain
region 103, an interfacial insulating layer 105 disposed to cover an upper surface
of the channel 104, a ferroelectric layer 106 disposed to cover an upper surface of
the interfacial insulating layer 105, and a gate electrode 107 disposed to cover an
upper surface of the ferroelectric layer 106. In addition, the semiconductor device
100 may further include a substrate 101. The first source/drain region 102 and the
second source/drain region 103 may be disposed on two sides of an upper surface of
the substrate 101. The channel 104 may be a portion of the substrate 101.
[0043] Although not shown, the semiconductor device 100 may further include source/drain
contacts/electrodes respectively disposed on the first source/drain region 102 and
the second source/drain region 103. In addition, between the first source/drain region
102 and the source/drain electrode and between the second source/drain region 103
and the source/drain electrode, additional functional layers may further be disposed
to reduce a contact resistance and/or to prevent or reduce the likelihood of and/or
the impact from metal diffusion between a semiconductor and a metal.
[0044] The first source/drain region 102 and the second source/drain region 103 may be doped
to a first conductivity type, and the channel 104 and/or the substrate 101 may be
doped to a second conductivity type that is electrically opposite to the first conductivity
type. For example, the substrate 101 or the channel 104 may include a p-type semiconductor
and the first source/drain region 102 and the second source/drain region 103 may include
an n-type semiconductor, or the substrate 101 or the channel 104 may include an n-type
semiconductor and the first source/drain region 102 and the second source/drain region
103 may include a p-type semiconductor. The substrate 101 or the channel 104 may be
doped at a relatively low concentration in a range of about 10
14/cm
3 to about 10
18/cm
3 while the first source/drain region 102 and the second source/drain region 103 may
be doped at a relatively high concentration in a range of about 10
19/cm
3 to about 10
21/cm
3 for low resistance; however, example embodiments are not limited thereto. The first
source/drain region 102 and the second source/drain region 103 may be respectively
formed by doping both sides of an upper surface of the substrate 101. An upper region
of the substrate 101 in which the first source/drain region 102 and the second source/drain
region 103 are not formed is or corresponds to the channel 104. Accordingly, the channel
104 may be disposed between the first source/drain region 102 and the second source/drain
region 103.
[0045] The substrate 101, the first source/drain region 102, and the second source/drain
region 103 may include at least one of, for example, a Group IV semiconductor, such
as one or more of silicon (Si), germanium (Ge), SiGe, etc., a Group III-V compound
semiconductor, such as one or more of GaAs, GaP, etc., a Group II-VI compound semiconductor,
an oxide semiconductor, and a two-dimensional material semiconductor. When the substrate
101, the first source/drain region 102, and the second source/drain region 103 include
one or more of Si, Ge, SiGe, etc., the substrate 101 or channel 104 may be doped with
at least one dopant among B, Al, Ga, and In, and the first source/drain region 102
and the second source/drain region 103 may be doped with at least one dopant among
P, As, and Sb. Then, the semiconductor device 100 is or corresponds to or includes
an n-channel metal oxide semiconductor field effect transistor (NMOS). Alternatively,
the substrate 101 or channel 104 may be doped with at least one dopant among P, As,
and Sb, and the first source/drain region 102 and the second source/drain region 103
may be doped with at least one dopant among B, Al, Ga, and In. Then, the semiconductor
device 100 is or corresponds to or includes a p-channel metal oxide semiconductor
field effect transistor (PMOS).
[0046] The gate electrode 107 may have a conductivity of about 1 Mohm/square or less. The
gate electrode 107 may include one or more selected from the group consisting of or
including metal, metal nitride, metal carbide, polysilicon such as doped polysilicon,
and combinations thereof. For example, the metal may include aluminum (Al), tungsten
(W), molybdenum (Mo), titanium (Ti), or tantalum (Ta), and the metal nitride film
may include a titanium nitride film (TiN film) or a tantalum nitride film (TaN film),
and the metal carbide may be metal carbide doped (or including) aluminum or silicon,
and specific examples may include one or more of TiAIC, TaAIC, TiSiC and TaSiC. The
gate electrode 107 may have a structure in which a plurality of materials are stacked.
For example, the gate electrode 107 may have a stacked structure of a metal nitride
layer/metal layer, such as TiN/AI, or a stacked structure of a metal nitride layer/metal
carbide layer/metal layer, such as TiN/TiAIC/W. The gate electrode 107 may include
a titanium nitride film (TiN) or molybdenum (Mo), and the above example may be used
in variously modified forms. Alternatively or additionally, the gate electrode 107
may include a conductive two-dimensional material in addition to the materials described
above. For example, the conductive two-dimensional material may include at least one
of graphene, black phosphorus, amorphous boron nitride, two-dimensional hexagonal
nitride boron (h-BN), and phosphorene.
[0047] The ferroelectric layer 106 may include a ferroelectric material. A ferroelectric
or ferroelectric material is a material having a ferroelectricity that maintains spontaneous
polarization by aligning internal electric dipole moments even when no electric field
is applied from the outside. A threshold voltage of the semiconductor device 100 may
be changed according to a polarization direction of the ferroelectric layer 106, for
example, a direction from the gate electrode 107 to the channel 104 or vice versa
from the channel 104 to the gate electrode 107. In this regard, the semiconductor
device 100 may be a ferroelectric field effect transistor (FeFET). The semiconductor
device 100 may be applied to, for example, a non-volatile memory device and/or a logic
device.
[0048] The polarization direction of the ferroelectric layer 106 may be changed by applying
an electric field greater than or equal to a coercive field to the ferroelectric layer
106. When a voltage is applied to the gate electrode 107 to change the polarization
direction of the ferroelectric layer 106, an electric field is applied to the ferroelectric
layer 106 and the interfacial insulating layer 105, respectively. A ratio of an electric
field applied to the ferroelectric layer 106 to an electric field applied to the interfacial
insulating layer 105 may be determined by a ratio of dielectric constant of the ferroelectric
layer 106 to the dielectric constant of the interfacial insulating layer 105 and the
intensity of remnant polarization of the ferroelectric layer 106.
[0049] According to some example embodiments, in order to increase the ratio of the electric
field applied to the ferroelectric layer 106 and/or decrease the ratio of the electric
field applied to the interfacial insulating layer 105, an appropriate combination
of the dielectric constant of the interfacial insulating layer 105 and the remnant
polarization of the ferroelectric layer 106 is provided. For example, the polarization
change of the ferroelectric layer 106 may be calculated by using the Landau Khalatnikov
equation based on parameters, such as an initial gate voltage and the polarization
of the ferroelectric layer 106, and based on the calculation result, the change in
electric field applied to the interfacial insulating layer 105 may be calculated by
using Maxwell's equations. Computational simulation may be performed by repeating
the above calculations until the polarization of the ferroelectric layer 106, the
electric field applied to the ferroelectric layer 106, and the electric field applied
to the interfacial insulating layer 105 reach an equilibrium state.
[0050] FIG. 2 is a graph showing a relationship between a combination of the dielectric
constant k
IL of the interfacial insulating layer 105 and the remnant polarization Pr of the ferroelectric
layer 106 and the intensity of an electric field E
IL applied to the interfacial insulating layer 105. Unless otherwise specified, as used
herein the dielectric constant k
IL is unitless, the remnant polarization Pr has units of micro-coulombs per square centimeter,
and the electric field E
IL has units of megavolts per centimeter. In the graph of FIG. 2, the horizontal axis
indicates the dielectric constant k
IL of the interfacial insulating layer 105 and the vertical axis indicates the electric
field E
IL applied to the interfacial insulating layer 105. Referring to FIG. 2, as the dielectric
constant of the interfacial insulating layer 105 increases, the intensity of the electric
field applied to the interfacial insulating layer 105 may decrease. Also, as the intensity
of the remnant polarization of the ferroelectric layer 106 decreases, the intensity
of the electric field applied to the interfacial insulating layer 105 may decrease.
The dielectric constant of the interfacial insulating layer 105 and the remnant polarization
of the ferroelectric layer 106 may be selected so that a voltage less than a breakdown
voltage of the interfacial insulating layer 105 is applied to the interfacial insulating
layer 105 while an operating voltage is applied to the gate electrode 107.
[0051] For example, the dielectric constant of the interfacial insulating layer 105 and
the remnant polarization of the ferroelectric layer 106 may be selected so that an
electric field of 10 MV/m or less is applied to the interfacial insulating layer 105.
Referring to FIG. 2, when the remnant polarization of the ferroelectric layer 106
is 0.1 uC/cm
2 or more and 5 uC/cm
2 or less, the dielectric constant of the interfacial insulating layer 105 may be about
7 or more. Alternatively or additionally, when the remnant polarization of the ferroelectric
layer 106 is 0.1 uC/cm
2 or more and 10 uC/cm
2 or less, the dielectric constant of the interfacial insulating layer 105 may be about
14 or more. Alternatively or additionally, the remnant polarization of the ferroelectric
layer 106 is 0.1 uC/cm
2 or more and 15 uC/cm
2 or less, the dielectric constant of the interfacial insulating layer 105 may be about
22 or more. Therefore, if more generalized, when the numerical value of the dielectric
constant of the interfacial insulating layer 105 is K and unitless, and the numerical
value of the remnant polarization of the ferroelectric layer 106 is Pr in units of
uC/cm
2, materials of the interfacial insulating layer 105 and the ferroelectric layer 106
may be selected so that K/Pr is about 1 or more. Here, Pr represents a numerical value
when the unit of remnant polarization is set to uC/cm
2. In addition, the dielectric constant represents a relative permittivity, and K is
a dimensionless numerical value. The remnant polarization of the ferroelectric layer
106 may correspond to remnant polarization of the semiconductor device 100. Therefore,
the remnant polarization of the ferroelectric layer 106 may be estimated by measuring
the remnant polarization of the semiconductor device 100. The dielectric constant
of the interfacial insulating layer 105 may be estimated from the composition of the
interfacial insulating layer 105.
[0052] The above-described numerical values relating to the breakdown voltage of the interfacial
insulating layer 105, the remnant polarization of the ferroelectric layer 106, and
the dielectric constant of the interfacial insulating layer 105 are merely examples.
The breakdown voltage of the interfacial insulating layer 105 may vary depending on
the material of the interfacial insulating layer 105 and/or of various defects in
the material of the interfacial insulating layer 105. In addition, the remnant polarization
of the ferroelectric layer 106 and the dielectric constant of the interfacial insulating
layer 105 may also vary according to a change in the breakdown voltage. However, no
matter what materials are selected as the materials of the interfacial insulating
layer 105 and the ferroelectric layer 106, the overall tendency shown in the graph
of FIG. 2 may be maintained.
[0053] An insulating dielectric material of the interfacial insulating layer 105 satisfying
the dielectric constant condition described above may include at least one material
selected from, for example, metal-silicon-oxide, metal-silicon-nitride, metal-silicon-oxynitride,
metal-germanium-oxide, metal-germanium-oxynitride, metal-silicon-germanium-oxide,
metal-silicon-germanium-nitride, and metal-silicon-germanium-oxynitride. In other
words, the interfacial insulating layer 105 may include at least one material selected
from M-Si
xGe
1-x-O (0≤x≤1) and M-Si
xGe
1-x-O
yN
1-y (0≤x≤1, 0≤y≤1). Here, M represents a metal material. The metal material may include,
for example, at least one material selected from Ti, Al, Hf, Zr, La, Y, Mg, and Be,
or a combination thereof. When the channel 104 includes silicon, the interfacial insulating
layer 105 may also include silicon, and when the channel 104 includes germanium, the
interfacial insulating layer 105 may also include germanium.
[0054] FIG. 3 is a graph showing a comparison of a capacitance-voltage characteristic of
two semiconductor devices including interfacial insulating layers 105 having different
dielectric constant. For example, the interfacial insulating layer 105 of the semiconductor
device 100 according to various example embodiments includes HfSiON, and the interfacial
insulating layer of the semiconductor device according to a comparative example includes
SiO
2 but may not include HfSiON. The capacitance represents a measured capacitance of
a capacitor formed between the gate electrode 107 and the channel 104, and the voltage
represents a gate voltage. Referring to the graph of FIG. 3, because the dielectric
constant of HfSiON is greater than that of SiO
2, when an operating voltage is applied to the gate electrode 107, it may be seen that
the capacitance of the semiconductor device 100 according to various embodiments is
greater than that of the semiconductor device according to the comparative example.
[0055] FIG. 4 is a graph showing a comparison of switching voltages of two semiconductor
devices each including an interfacial insulating layer 105 and having dielectric constants
different from each other. In the graph of FIG. 4, the current represents a displacement
current between the gate electrode 107 and the substrate 101. Because the dielectric
constant of HfSiON is greater than that of SiO
2, when the same voltage is applied to the gate electrode, an electric field applied
to the ferroelectric layer 106 of the semiconductor device 100 according to the embodiment
is greater than an electric field applied to the ferroelectric layer of the semiconductor
device according to the comparative example. Accordingly, as it may be seen from the
graph of FIG. 4, a switching voltage S1 of the semiconductor device 100 according
to the embodiment may be less than a switching voltage S2 of the semiconductor device
according to the comparative example. Accordingly, the operating voltage of the semiconductor
device 100 according to various example embodiments may be reduced.
[0056] The remnant polarization of the ferroelectric layer 106 may be determined by one
or more of a type of material of the ferroelectric layer 106, a type of dopant, a
ratio of the dopant, an orientation, and the like. For example, the ferroelectric
layer 106 may include one or more oxides of one or more of Si, Al, Hf, and Zr, and/or
a two-dimensional ferroelectric material. In addition, the two-dimensional ferroelectric
material may include at least one material selected from 1T-MoS
2, SnTe, GeSe, 1T-MoTe
2, In
2Se
3, and CuInP
2S
6. The ferroelectric layer 106 may be configured so that the intensity of the remnant
polarization is, for example, 15 uC/cm
2 or less, 10 uC/cm
2 or less, or 5 uC/cm
2 or less. Alternatively or additionally, the ferroelectric layer 106 may be configured
to have a coercive field in a range of 30 kV/cm to 3 MV/cm or less.
[0057] In order to control the remnant polarization and the coercive field, the ferroelectric
layer 106 may further include a dopant doped in the oxide described above or in a
two-dimensional ferroelectric material. For example, the dopant may include at least
one material selected from Si, Al, Y, La, Gd, Mg, Ca, Sr, Ba, Ti, Zr, Hf, and N. Alternatively
or additionally, the ferroelectric layer 106 may include at least two dopants different
from each other. The remnant polarization and coercive field of the ferroelectric
layer 106 may vary depending on a ratio of dopants in the ferroelectric layer 106.
[0058] FIG. 5 is a graph showing a comparison of remnant polarizations of two ferroelectric
layers 106 having different doping concentrations from each other. HfO
2 is used as a material of the ferroelectric layer 106 and Zr is used as a dopant.
Referring to the graph of FIG. 5, when a ratio of Zr is 50 at% (indicated by a thick
solid line), the remnant polarization of the ferroelectric layer 106 is about 22 uC/cm
2. Further, when the ratio of Zr is 30 at% (indicated by a thin solid line), the remnant
polarization of the ferroelectric layer 106 is about 16 uC/cm
2.
[0059] As it may be seen from the graph of FIG. 5, when the ratio of the Zr dopant in the
ferroelectric layer 106 including HfO
2 is decreased from 50 at% to 30 at%, the remnant polarization decreases. In either
case, because the remnant polarization shows a clear hysteresis curve, the ferroelectric
layer 106 may operate as a memory cell/memory unit. When using HfO
2 as the material of the ferroelectric layer 106 and Zr as the dopant, the ratio of
the dopant in the ferroelectric layer 106 may be selected, for example, from 0 at%
to about 90 at%. Meanwhile, another material may be used as a dopant instead of Zr,
and in this case, a ratio of the dopant in the ferroelectric layer 106 may vary. In
the case of using a material other than Zr, such as Si, Al, etc., a ratio of the dopant
in the ferroelectric layer 106 may be, for example, in a range from about 0 at% to
about 20 at%.
[0060] Also, FIG. 6 is a graph showing a comparison of characteristics of two semiconductor
devices each including ferroelectric layers having doping concentrations different
from each other. HfO
2 is used as a material of the ferroelectric layer 106 and Zr is used as a dopant,
and the measurement was performed after 1000 set-reset operations/program-erase operations
were performed on the ferroelectric layer 106. In addition, in the graph of FIG. 6,
Vgs is a gate voltage applied to the gate electrode 107 and the current is a current
flowing between the first source/drain region 102 and the second source/drain region
103. Referring to FIG. 6, when the ratio of Zr is 50 at% (indicated by a thick solid
line and a dashed line), for example, when a remnant polarization is relatively high,
the ferroelectric layer 106 does not operate as a memory after 1000 set-reset operations.
On the other hand, when the ratio of Zr is 30 at% (indicated by a thin solid line
and a dashed line), for example, when the remnant polarization is relatively low,
it may be seen that, even after 1000 set-reset operations, the ferroelectric layer
106 may operate as a memory, e.g. memory cell/memory unit capable of storing one or
more bits, and may or may not be non-volatile.
[0061] In order to reduce the influence of the interfacial insulating layer 105 in the semiconductor
device 100, a thickness of the interfacial insulating layer 105 may be less than that
of the ferroelectric layer 106. For example, the thickness of the interfacial insulating
layer 105 may be less than or equal to about 2 nm, e.g., in a range from about 0.1
nm to about 2 nm. The thickness of the ferroelectric layer 106 may be, for example,
in a range from about 4 nm to about 20 nm. For example, the thickness of the ferroelectric
layer 106 may be about 2 to about 200 times the thickness of the interfacial insulating
layer 105.
[0062] As described above, by appropriately combining the dielectric constant of the interfacial
insulating layer 105 and the remnant polarization of the ferroelectric layer 106,
the intensity of the electric field applied to the interfacial insulating layer 105
may be reduced. Then, in order to apply an electric field having an intensity equal
to or greater than a coercive field to the ferroelectric layer 106, a voltage greater
than a breakdown voltage is prevented or reduced in likelihood of occurrence and/or
impact from being applied to the interfacial insulating layer 105, thereby preventing
or reducing the likelihood of occurrence of and/or impact of the formation of a charge
trap in the interfacial insulating layer 105. Accordingly, durability of the semiconductor
device 100 may be improved. Alternatively or additionally, because the intensity of
the electric field applied to the interfacial insulating layer 205 may be reduced
and the intensity of the electric field applied to the ferroelectric layer 206 may
be increased, an operating voltage of the semiconductor device 100 may decrease, and
power consumption of the semiconductor device 100 may be reduced and operating efficiency
of the semiconductor device 100 may be improved. Alternatively or additionally, data
retention of the semiconductor device 100 may be improved by reducing a depolarization
field.
[0063] FIG. 7 is a schematic cross-sectional view illustrating a structure of a semiconductor
device 100a according to some example embodiments. Referring to FIG. 7, the semiconductor
device 100a may further include a conductor layer 108 disposed between the interfacial
insulating layer 105 and the ferroelectric layer 106. The conductor layer 108 may
include, for example, the same conductive material as the gate electrode 107. The
conductor layer 108 may be a floating gate to which a voltage is not applied from
an external power source.
[0064] When the conductor layer 108 is disposed between the interfacial insulating layer
105 and the ferroelectric layer 106, two capacitors connected in series may be formed
in the semiconductor device 100a. For example, a lower capacitor may be formed between
the channel 104 and the conductor layer 108, and an upper capacitor may be formed
between the gate electrode 107 and the conductor layer 108. In the lower capacitor,
charges may be accumulated in the interfacial insulating layer 105, and in the upper
capacitor, charges may be accumulated in the ferroelectric layer 106. In order to
further reduce the intensity of an electric field applied to the interfacial insulating
layer 105, the capacitance of the lower capacitor may be increased and/or the capacitance
of the upper capacitor may be decreased. To this end, a width or diameter W2 of the
interfacial insulating layer 105 and the conductor layer 108 may be greater than a
width or diameter W1 of the ferroelectric layer 106 and the gate electrode 107. In
other words, a sum of an area of a surface of the interfacial insulating layer 105
that contacts the conductor layer 108 and an area of a surface of the conductor layer
108 that contacts the interfacial insulating layer 105 may be greater than a sum of
an area of a surface of the ferroelectric layer 106 that contacts the gate electrode
107 and an area of a surface of the gate electrode 107 that contacts the ferroelectric
layer 106. The remaining components of the semiconductor device 100a that are not
described may be the same as those of the semiconductor device 100 shown in FIG. 1,
and thus, detailed descriptions thereof are omitted.
[0065] FIG. 8 is a schematic cross-sectional view illustrating a structure of a semiconductor
device 100b according to some example embodiments. Referring to FIG. 8, the semiconductor
device 100b may further include spacers Sp1 and Sp2 that are on a sidewall of the
stack including the interfacial insulating layer 105 the ferroelectric layer 106,
and the gate electrode 107.
[0066] There may be a lightly doped region S' within the substrate 101 adjacent to the first
source/drain region 102, and a lightly doped region D' within the substrate 101 adjacent
to the second source/drain region 103. The channel 104 may be arranged between the
lightly doped region S' and the lightly doped region D'.
[0067] A dopant concentration of either or both of the lightly doped region S' and the lightly
doped region D' may be lower than the dopant concentration of either or both of the
first source/drain region 102 and the second source/drain region 103.
[0068] The interfacial insulating layer 105 may be directly on the substrate 101. There
may not be another oxide, such as another gate oxide, between the interfacial insulating
layer 105 and the substrate 101.
[0069] In FIGS. 1, 7 and 8, although the semiconductor devices 100, 100a and 100b are illustrated
as field effect transistors having a planar channel 104, example embodiments are not
limited thereto. For example, the concept according to the embodiments described above
may be applied to a FinFET, a gate-all-around FET (GAAFET), or a multi-bridge channel
FET (MBCFET
™) having a three-dimensional channel structure.
[0070] FIG. 9 is a schematic cross-sectional view illustrating a structure of a semiconductor
device according to some example embodiments. Referring to FIG. 9, the semiconductor
device 200 may include a substrate 201, a first source/drain region 202 protruding
in a Z-direction from an upper surface of the substrate 201, a second source/drain
region 203 protruding in the Z-direction from the upper surface of the substrate 201,
a channel 204 protruding from the upper surface of the substrate 201 in the Z-direction
and having a bar shape extending in a Y-direction, an interfacial insulating layer
205 surrounding and covering the channel 204, a ferroelectric layer 206 surrounding
and covering the interfacial insulating layer 205, and a gate electrode 207 surrounding
and covering the ferroelectric layer 206. The semiconductor device 200 may further
include a device isolation layer 209 to electrically separate the semiconductor device
200 from other adjacent semiconductor devices (not shown). The device isolation layer
209 may include an insulating dielectric material, and may be disposed to extend in
the Y-direction along both sides of the first source/drain region 202, the channel
204, and the second source/drain region 203 on the upper surface of the substrate
201. The semiconductor device 200 shown in FIG. 9 may be or may include, for example,
a FinFET.
[0071] The channel 204 may extend in the Y-direction to be connected between the first source/drain
region 202 and the second source/drain region 203. In other words, a first end of
the channel 204 may contact the first source/drain region 202 and a second end of
the channel 204 may contact the second source/drain region 203. The channel 204 may
include a relatively lightly doped p-type semiconductor or a relatively lightly doped
n-type semiconductor.
[0072] FIG. 10 is a schematic cross-sectional view showing a gate structure of the semiconductor
device 200 shown in FIG. 9, in particular, a cross-sectional view taken along line
A-A' of the gate structure. Referring to FIG. 10, the interfacial insulating layer
205 may be disposed to protrude from an upper surface of the substrate 201 to cover
three surfaces of the channel 204, for example, both side surfaces and an upper surfaces
of the channel 204. Alternatively or additionally, the ferroelectric layer 206 may
be disposed to protrude from the upper surface of the substrate 201 so as to cover
three surfaces of the interfacial insulating layer 205, that is, both side surfaces
and an upper surface of the interfacial insulating layer 205. The gate electrode 207
may be disposed to protrude from the upper surface of the substrate 201 so as to cover
three surfaces of the ferroelectric layer 206, For example, both side surfaces and
an upper surface of the ferroelectric layer 206.
[0073] FIGS. 9 and 10 show an example in which the semiconductor device 200 is formed by
using a bulk semiconductor substrate. In this case, the channel is a central region
of an upper portion of the semiconductor substrate remaining after etching both upper
regions of the semiconductor substrate. Instead of the bulk substrate, it is also
possible to form a semiconductor device on a silicon on insulator (SOI) substrate.
[0074] FIG. 11 is a schematic perspective view showing a structure of a semiconductor device
200a according to some example embodiments, and FIG. 12 is a schematic cross-sectional
view showing a gate structure of the semiconductor device 200a shown in FIG. 11, in
particular, a cross-sectional view taken along line B-B' of the gate structure. Referring
to FIGS. 11 and 12, the semiconductor device 200a includes a substrate 201, an insulating
layer 210 on the substrate 201, a first source/drain region 202 protruding in a Z-direction
from an upper surface of the insulating layer 210, a second source/drain region 203
protruding in the Z-direction from the upper surface of the insulating layer 210,
a channel 204 protruding in the Z-direction from the upper surface of the insulating
layer 210 and having an extended bar shape, an interfacial insulating layer 205 surrounding
and covering three side surfaces of the channel 204, a ferroelectric layer 206 surrounding
and covering three side surfaces of the interfacial insulating layer 205, and a gate
electrode 207 surrounding and covering three side surfaces of the layer 206. The substrate
201 and the insulating layer 210 may form an SOI substrate including silicon and SiO
2, respectively. The first source/drain region 202, the second source/drain region
203, and the channel 204 may be formed by depositing on the insulating layer 210,
e.g. depositing with at least one of a chemical vapor deposition (CVD) process and
an atomic layer deposition (ALD) process.
[0075] FIG. 13 is a schematic cross-sectional view illustrating a structure of a semiconductor
device 200b according to some example embodiments. Referring to FIG. 13, the semiconductor
device 200b includes a substrate 201, a first source/drain region 202 protruding in
the Z-direction from an upper surface of the substrate 201, a second source/drain
region 203 protruding in the Z-direction from the upper surface of the substrate 201,
a channel 204 separated from the upper surface of the substrate 201 and having a bar
shape extending in the Y-direction, an interfacial insulating layer 205 surrounding
and covering the channel 204, a ferroelectric layer 206 surrounding and covering the
interfacial insulating layer 205, and a gate electrode 207 surrounding and covering
the ferroelectric layer 206. The channel 204 may include a plurality of channel elements
204a, 204b, 204c disposed at a distance from each other in the Z-direction or an X
direction that is different from the Y-direction. In FIG. 13, although the three channel
elements 204a, 204b, and 204c are illustrated as being separated from each other in
the Z-direction, this is merely an example and is not necessarily limited thereto.
The semiconductor device 200b illustrated in FIG. 13 may be, for example, a GAAFET
or an MBCFET
™.
[0076] FIG. 14 is a schematic cross-sectional view showing a gate structure of the semiconductor
device 200b shown in FIG. 13, and in particular, a cross-sectional view taken along
line C-C' of the gate structure. Referring to FIG. 14, the semiconductor device 200b
may include a plurality of interfacial insulating layers 205 disposed to respectively
surround four surfaces of the plurality of channel elements 204a, 204b, and 204c.
Also, the semiconductor device 200b may include a plurality of ferroelectric layers
206 disposed to respectively surround four surfaces of the plurality of interfacial
insulating layers 205. The gate electrode 207 may have a structure extending in the
Z-direction by protruding from an upper surface of the substrate 201 to surround four
surfaces of each of the plurality of ferroelectric layers 206.
[0077] Principles described with reference to FIGS. 1 to 6 may be applied to the interfacial
insulating layer 205 and the ferroelectric layer 206 of the semiconductor devices
200, 200a, and 200b shown in FIGS. 9 to 14.
[0078] The semiconductor devices described above may be employed in various electronic apparatuses.
For example, the semiconductor devices described above may be used as logic transistors
and/or as memory transistors. Alternatively or additionally, the semiconductor devices
described above may be used as memory cells. A plurality of memory cells in a two-dimensional
arrangement, in a vertical or horizontal direction arrangement, or a one direction
arrangement may form a memory cell string. A memory cell array may be formed in a
form according to the two-dimensionally disposed memory cell strings. In addition,
the semiconductor devices described above may constitute or be included as a part
of an electronic circuit that constitutes an electronic apparatus together with other
circuit elements, such as a capacitor.
[0079] FIG. 15 is a schematic circuit diagram of a memory device 300 including a semiconductor
device array. Referring to FIG. 15, the memory device 300 may include an array of
the plurality of semiconductor devices 100 two dimensionally disposed. Also, the memory
device 300 may include a plurality of columns/bit lines BL0 and BL1, a plurality of
selection lines SL0 and SL1, and a plurality of rows/word lines WL0 and WL1. The selection
lines SL0 and SL1 may be electrically connected to a first source/drain region of
the semiconductor device 100, the bit lines BL0 and BL1 may be electrically connected
to a second source/drain region of the semiconductor device 100, and the plurality
of word lines WL0 and WL1 may be electrically connected to a gate electrode of the
semiconductor device 100. Also, the memory device 300 may further include an amplifier
310 such as a sense amplifier that is configured to amplify a signal output from the
bit lines BL0 and BL1. Each semiconductor device 100 may be one memory cell of the
memory device 400.
[0080] In FIG. 15, although the memory device 300 is illustrated as a two-dimensional plane
for convenience, the memory device 300 may have a stacked structure of two or more
layers. For example, a plurality of bit lines BL0 and BL1 and a plurality of selection
lines SL0 and SL1 extending in a vertical direction may be two-dimensionally disposed,
and a plurality of word lines WL0 and WL1 extending in a horizontal direction may
be respectively disposed in a plurality of layers. However, the present inventive
concept is not limited thereto, and the memory cells may be three- dimensionally (3D)
disposed in various ways.
[0081] FIG. 16 is a schematic cross-sectional view illustrating a structure of a semiconductor
device according to some example embodiments. The semiconductor device 400 in FIG.
16 may be a memory cell string of a three-dimensional (or a vertical) NAND (or VNAND)
or a three-dimensional FeFET memory. Referring to FIG. 16, the semiconductor device
400 may include a plurality of insulating spacers 401 and a plurality of gate electrodes
402 that are alternately stacked in the vertical direction. The plurality of insulating
spacers 401 and the plurality of gate electrodes 402 extend in the horizontal direction.
The insulating spacers 401 may include, for example, a silicon oxide, but are not
limited thereto. Each of the gate electrodes 402 may be connected to a word line,
or each of the gate electrodes 402 may be directly a word line.
[0082] Also, the semiconductor device 400 may include a channel hole penetrating the plurality
of insulating spacers 401 and the plurality of gate electrodes 402 in the vertical
direction. A plurality of layers may be arranged on an inner side of the channel hole.
For example, the semiconductor device 400 may include an dielectric filler 406 arranged
in a center of the channel hole and extending in the vertical direction, a channel
layer 405 surrounding the dielectric filler 406 and extending in the vertical direction,
an interfacial insulating layer 404 surrounding the channel layer 405 and extending
in the vertical direction, and a ferroelectric layer 403 surrounding the interfacial
insulating layer 404 and extending in the vertical direction. The ferroelectric layer
403 may be arranged between the interfacial insulating layer 404 and the plurality
of gate electrodes 402. The dielectric filler 406, the channel layer 405, the interfacial
insulating layer 404, and the ferroelectric layer 403 may be arranged in a concentric
circular shape. Principles described with reference to FIGS. 1 to 6 may be applied
to the interfacial insulating layer 404 and the ferroelectric layer 403 of the semiconductor
device 400 in FIG. 16.
[0083] FIG. 17 is a schematic block diagram of a display driver IC (DDI) 500 and a display
device 520 including the DDI 500 according to some example embodiments. Referring
to FIG. 17, the DDI 500 may include a controller 502, a power supply circuit 504,
a driver block 506, and a memory block 508. The controller 502 receives and decodes
a command applied from a main processing unit (MPU) 522, and controls each block of
the DDI 500 to implement an operation in response to the command. The power supply
circuit 504 generates a driving voltage in response to control of the controller 502.
The driver block 506 drives the display panel 524 by using the driving voltage generated
by the power supply circuit 504 in response to the control of the controller 502.
The display panel 524 may include, for example, a liquid crystal display panel, an
organic light emitting device (OLED) display panel, or a plasma display panel. The
memory block 508 is a block for temporarily storing commands input to the controller
502 or control signals output from the controller 502 or for storing necessary data,
and may include a memory, such as RAM or ROM. For example, the memory block 508 may
include the semiconductor devices according to the embodiments described above.
[0084] FIG. 18 is a block diagram illustrating an electronic apparatus 600 according to
some example embodiments. Referring to FIG. 18, the electronic apparatus 600 includes
a memory 610 and a memory controller 620. The memory controller 620 may control the
memory 610 to read data from and/or write data to the memory 610 in response to a
request from a host 630. The memory 610 may include the semiconductor device according
to the embodiments described above.
[0085] FIG. 19 is a block diagram of an electronic apparatus 700 according to some example
embodiments. Referring to FIG. 19, an electronic apparatus 700 may constitute a wireless
communication device, or a device capable of transmitting and/or receiving information
in a wireless environment. The electronic apparatus 700 includes a controller 710,
an input/output (I/O) device 720, a memory 730, and a wireless interface 740, which
are interconnected through a bus 750.
[0086] The controller 710 may include at least one of a microprocessor, a digital signal
processor, and a processing apparatus similar thereto. The I/O device 720 may include
at least one of a keypad, a keyboard, and a display. The memory 730 may be used to
store commands executed by controller 710. For example, the memory 730 may be used
to store user data. The electronic apparatus 700 may use the wireless interface 740
to transmit/receive data through a wireless communication network. The wireless interface
740 may include an antenna and/or a wireless transceiver. In some embodiments, the
electronic apparatus 700 may be used for a communication interface protocol of a third
generation communication system, for example, one or more of a code division multiple
access (CDMA), a global system for mobile communications (GSM), a north American digital
cellular (NADC), an extended-time division multiple access (E-TDMA), and/or a wide
band code division multiple access (WCDMA). The memory 730 of the electronic apparatus
700 may include the semiconductor device according to the embodiments described above.
[0087] FIGS. 20 and 21 are schematic conceptual diagrams illustrating a device architecture
applicable to an electronic apparatus according to some example embodiments.
[0088] Referring to FIG. 20, an electronic device architecture 1000 may include a memory
unit 1010 and a control unit 1030, and may further include an arithmetic logic unit
(ALU) (1020). The memory unit 1010, the ALU 1020, and the control unit 1030 may be
electrically connected to each other. For example, the electronic device architecture
1000 may be implemented as one chip including the memory unit 1010, the ALU 1020,
and the control unit 1030. Specifically, the memory unit 1010, the ALU 1020, and the
control unit 1030 may be interconnected through a metal line in an on-chip to directly
communicate with each other. The memory unit 1010, the ALU 1020, and the control unit
1030 may be monolithically integrated on one substrate to constitute one chip. An
I/O device 2000 may be connected to the electronic device architecture (chip) 1000.
Also, the memory unit 1010 may include both a main memory and a cache memory. The
electronic device architecture (chip) 1000 may be an on-chip memory processing unit.
The memory unit 1010, the ALU 1020, and/or the control unit 1030 may each independently
include the semiconductor device according to the embodiments described above.
[0089] Referring to FIG. 21, a cache memory 1510, an ALU 1520, and a control unit 1530 may
constitute a central processing unit (CPU) 1500, and the cache memory 1510 may include
a static random access memory (SRAM). Separately from the CPU 1500, a main memory
1600 and an auxiliary storage 1700 may be provided, and an I/O device 2500 may be
provided. The main memory 1600 may be, for example, a dynamic random access memory
(DRAM) and may include the semiconductor device according to the embodiments described
above.
[0090] In some cases, an electronic device architecture may be implemented in a form in
which computing unit devices and memory unit devices are adjacent to each other in
a single chip without distinction of sub-units.
[0091] Any of the elements and/or functional blocks disclosed above may include or be implemented
in processing circuitry such as hardware including logic circuits; a hardware/software
combination such as a processor executing software; or a combination thereof. For
example, the processing circuitry more specifically may include, but is not limited
to, a central processing unit (CPU), an arithmetic logic unit (ALU), a digital signal
processor, a microcomputer, a field programmable gate array (FPGA), a System-on-Chip
(SoC), a programmable logic unit, a microprocessor, application-specific integrated
circuit (ASIC), etc. The processing circuitry may include electrical components such
as at least one of transistors, resistors, capacitors, etc. The processing circuitry
may include electrical components such as logic gates including at least one of AND
gates, OR gates, NAND gates, NOT gates, etc.
[0092] It should be understood that various example embodiments described herein should
be considered in a descriptive sense only and not for purposes of limitation. Descriptions
of features or aspects within each embodiment and/or figure should typically be considered
as available for other similar features or aspects in other embodiments and/or figure,
and example embodiments are not necessarily mutually exclusive with one another. While
one or more embodiments have been described with reference to the figures, it will
be understood by those of ordinary skill in the art that various changes in form and/or
details may be made therein without departing from the scope as defined by the following
claims.
1. A semiconductor device comprising:
a first source/drain region;
a second source/drain region;
a channel between the first source/drain region and the second source/drain region;
an interfacial insulating layer on the channel;
a ferroelectric layer on the interfacial insulating layer; and
a gate electrode on the ferroelectric layer,
wherein a first material of the interfacial insulating layer and a second material
of the ferroelectric layer are such that K/Pr is 1 or more, where K is a numerical
value of dielectric constant of the interfacial insulating layer and Pr is a numerical
value in uC/cm2 of a remnant polarization of the ferroelectric layer.
2. The semiconductor device of claim 1, wherein the dielectric constant of the interfacial
insulating layer and the remnant polarization of the ferroelectric layer are such
that a voltage applied to the interfacial insulating layer during application of an
operating voltage to the gate electrode is less than a breakdown voltage of the interfacial
insulating layer.
3. The semiconductor device of either claim 1 or claim 2, wherein the dielectric constant
of the interfacial insulating layer is 22 or more, and the remnant polarization of
the ferroelectric layer is 0.1 uC/cm2 or more and 15 uC/cm2 or less.
4. The semiconductor device of any one of the preceding claims, wherein the dielectric
constant of the interfacial insulating layer is 7 or more, and the remnant polarization
of the ferroelectric layer is greater than or equal to 0.1 uC/cm2 and less than or equal to 5 uC/cm2.
5. The semiconductor device of any one of the preceding claims, wherein a coercive field
of the ferroelectric layer is in a range from 30 kV/cm to 3 MV/cm or less.
6. The semiconductor device of any one of the preceding claims, wherein the interfacial
insulating layer includes at least one material selected from M-SixGe1-x-O (0≤x≤1) and M-SixGe1-x-OyN1-y (0≤x≤1, 0≤y≤1), where M includes a metal material and, optionally, wherein the metal
material includes at least one material selected from Ti, Al, Hf, Zr, La, Y, Mg, and
Be or a combination thereof.
7. The semiconductor device of any one of the preceding claims, wherein the ferroelectric
layer includes an oxide selected from the group including silicon oxide, hafnium oxide,
and zirconium oxide, or the ferroelectric layer includes a two-dimensional ferroelectric
material and, optionally,wherein the ferroelectric layer further includes a dopant
doped in the oxide or the two-dimensional ferroelectric material, wherein the dopant
includes at least one material selected from the group including Si, Al, Y, La, Gd,
Mg, Ca, Sr, Ba, Ti, Zr, Hf and N.
8. The semiconductor device of claim 7, wherein the ferroelectric layer includes at least
two dopants different from each other and/or wherein a ratio of the dopant in the
ferroelectric layer is in a range from 0 at% to 90 at%.
9. The semiconductor device of claim 7, wherein the two-dimensional ferroelectric material
includes at least one material selected from the group including 1T-MoS2, SnTe, GeSe, 1T-MoTe2, In2Se3, and CuInP2S6.
10. The semiconductor device of any one of the preceding claims, further comprising:
a conductor layer between the interfacial insulating layer and the ferroelectric layer,
and, optionally, wherein a sum of an area of a surface of the interfacial insulating
layer in contact with the conductor layer and an area of a surface of the conductor
layer in contact with the interfacial insulating layer is greater than a sum of an
area of a surface of the ferroelectric layer in contact with the gate electrode and
an area of a surface of the gate electrode in contact with the ferroelectric layer.
11. The semiconductor device of any one of the preceding claims, further comprising:
a substrate,
wherein the channel protrudes from an upper surface of the substrate and has a shape
extending in a first direction.
12. The semiconductor device of claim 11, wherein the interfacial insulating layer surrounds
side surfaces and an upper surface of the channel,
the ferroelectric layer surrounds side surfaces and an upper surface of the interfacial
insulating layer, and
the gate electrode surrounds side surfaces and an upper surface of the ferroelectric
layer.
13. The semiconductor device of claim 12, wherein the channel includes a plurality of
channel elements at a distance from each other in a second direction that is different
from the first direction.
14. The semiconductor device of claim 13, wherein the interfacial insulating layer includes
a plurality of interfacial insulating layers to respectively surround the plurality
of channel elements,
the ferroelectric layer includes a plurality of ferroelectric layers to respectively
surround the plurality of interfacial insulating layers, and
the gate electrode protrudes from the upper surface of the substrate to surround the
plurality of ferroelectric layers.
15. An electronic apparatus comprising at least one semiconductor device according to
any one of the preceding claims.